An accelerometer is an instrument that measures the proper acceleration of the instrument, i.e. the type of acceleration associated with the phenomenon of weight experienced by a test mass residing in the frame of reference of the accelerometer and thus measures weight per unit of mass, a quantity also known as specific force or “g-force”. A multi-axis accelerometer is able to detect magnitude and direction of the proper acceleration as a vector quantity, and can be used to sense orientation (due to changes in direction of weight), coordinate acceleration, vibration, shock, and falling. Accelerometers are often used in portable or handheld or otherwise mobile devices such as cellular telephones, PDAs, smart phones, portable gaming devices, laptop computers, tablet computers; for orientation detection, motion inputs (e.g. for gaming), image stabilization (e.g. when taking photos), drop detection, etc.
The measurements taken by an accelerometer may be used by various applications or other components of the device in which it resides and thus the accuracy of the accelerometer can be important to the operation of the device.